Californians who use medical marijuana outside of work would be protected from job dismissal due to pot use under a bill that has been introduced by state Sen. Mark Leno, D-San Francisco.

The bill, SB129, would make it illegal for an employer to consider either a worker's status as a registered patient or a positive drug test when making hiring and firing decisions. The bill would not change existing laws that bar employees from using medical marijuana at the workplace or during work hours.

Workers such as health care providers, school bus drivers and operators of heavy equipment - so-called "safety-sensitive positions" - would not be protected by the law.

"The bill simply establishes a medical cannabis patient's right to work," Leno said. He called it "a completely reasonable piece of legislation. It astounds me that there would be any controversy around it."

While the proposal has yet to garner formal opposition, the California Chamber of Commerce opposed a bill that would have created the same protections for medical marijuana patients in 2007.

That bill, authored by Leno, was passed by the Legislature but vetoed by former Gov. Arnold Schwarzenegger. In his veto message, Schwarzenegger wrote he was "concerned with the interference in employment decisions as they relate to marijuana use" and that employment protection was not a goal of Prop. 215, which voters passed in 1996 to allow medical marijuana.

Leno said the notion that voters only intended for unemployed people to be able to take medical marijuana is "nonsensical on its face."

The effort to pass such a law stems from a California Supreme Court decision in 2008 that allowed employers to fire workers who test positive for marijuana use, even if those workers are medical marijuana patients. In a 5-2 decision, the court found Prop. 215 does not limit an employer's authority to fire workers for violating federal drug laws.

Marijuana possession and use is illegal under federal law.

A spokeswoman for the Chamber of Commerce said the organization could not comment until it examined the proposal. She did note the chamber's strong opposition to Prop. 19 - the failed November ballot measure to legalize possession, use and cultivation of recreational marijuana in the state - because of impacts on employers and safety issues.